Scaling an object of varied widths?
I would use Proportional Editing with a linear falloff.  Proportional editing applies any transform you use to neighbouring vertices with some sort of interpolated falloff.

You can enable Proportional Editing by pressing O.  While transforming you can scroll the mouse wheel up and down to adjust the falloff distance.  You can change the falloff gradient in the footer of the 3D view, to the left of the snapping controls.